Trinational Risk Assessment Guidelines
Commission for Environmental Cooperation
for Aquatic Alien Invasive Species
1
There are few environmental issues that are as well documented as the impacts of
alien invasive species. The movement of people, commodities and their conveyances
through international commerce has increased the risk of transfer of these unwanted
organisms. Although many non-native species provide great benefits to society as a
whole, a small subset of them, once established, will cause significant and often irreparable damage to the native ecosystems and economies of their new host countries.
Following the urging of its Joint Public Advisory Committee, the Council of the Commission for Environmental Cooperation (CEC) began to focus cooperative work on issues
related to alien invasive species and the Trinational Alien Invasive Species Project was
set in motion.
As aquatic invasive species are such a good example of the threat potentially posed
to biodiversity by international trade, the duly constituted Trinational Aquatic Alien
Invasive Species Working Group agreed to draft the CEC Trinational Aquatic Invasive
Species Risk Assessment Guidelines. The Working Group chose as a model the review
process developed in 1996 by the Aquatic Nuisance Species Task Force (ANSTF) in the
United States. The process also had the distinct advantages of being easily understood, meeting the requirements of the various international trade conventions and
agreements, and having been already widely tested on a number of organisms under
real world conditions. It is hoped that the resulting CEC Risk Assessment Guidelines
set forth in this document will prove useful and yet flexible enough to accommodate
new methodologies and processes that may become available, even if they are not intended as the final word upon which to base national regulatory action.
These guidelines are also available, along with risk assessments and socio-economic case studies, as Trinational Risk Assessment Guidelines for Aquatic Alien Invasive Species: Test Cases for the Snakeheads (Channidae) and Armored Catfishes (Loricariidae) in North American Inland Waters.
2
Trinational Risk Assessment Guidelines for Aquatic Alien Invasive Species
Trinational Risk Assessment Guidelines
for Aquatic Alien Invasive Species
Richard Orr (1) and Jeffrey P. Fisher (2)*
Introduction
In 1993, Canada, Mexico and the United States signed the North American Agreement on Environmental Cooperation (NAAEC)
as a side agreement to the North American Free Trade Agreement (NAFTA). The NAAEC established the Commission for Environmental Cooperation (CEC) to help the Parties ensure that improved economic efficiency occurred simultaneously with
trinational environmental cooperation. The NAAEC highlighted biodiversity as a key area for trinational cooperation. In 2001,
the CEC adopted a resolution (Council Resolution 01-03), which created the Biodiversity Conservation Working Group (BCWG),
a working group of high-level policy makers from Canada, Mexico and the United States. In 2003, the BCWG produced
the “Strategic Plan for North American Cooperation in the Conservation of Biodiversity.” This strategy identified responding to
threats, such as invasive species, as a priority action area. In 2004, the BCWG, recognizing the importance of prevention in addressing invasive species, agreed to work together to develop the draft CEC Risk Assessment Guidelines for Aquatic Alien Invasive
Species (hereafter referred to as the Guidelines). These Guidelines will serve as a tool to North American resource managers who are evaluating whether or not to introduce a non-native species into a new ecosystem. Through this collaborative
process, the BCWG has begun to implement its strategy as well as address an important trade and environment issue. With increased
trade comes an increase in the potential for economic growth as well as biological invasion, by working to minimize the potential adverse impacts from trade, the CEC Parties are working to maximize the gains from trade while minimizing the environmental costs.
Objectives of the Guidelines
The objective of the Guidelines is to provide a standardized process
for evaluating the risk to biodiversity of introducing aquatic nonindigenous organisms into a new environment.
The Guidelines provide a framework where scientific, technical, and other relevant information can be organized into a format
that is understandable and useful to managers and decision makers. The Guidelines were developed to function as an open process
with early and continuous input from the appropriate scientific
and technical experts.
The Guidelines were designed to be flexible and dynamic
enough to accommodate a variety of approaches in evaluating the
invasive potential of introduced aquatic species depending on the
available resources, accessibility of the biological information, and
the risk assessment methods available at the time of the assessment.
The Guidelines may be used as a purely subjective evaluation, or
be quantified to the extent possible or necessary, depending on the
needs of the analysis. Therefore, the process will accommodate a
full range of methodologies from a simple and quick professional
judgmental process to an analysis requiring extensive research and
sophisticated technologies.
The importance of conducting a high-quality risk assessment
is that it can provide a solid foundation for justifying corrective action. The specific function of the Guidelines is to present a process
that can be used to: (1) evaluate recently established non-indigenous
organisms, and (2) evaluate the risk associated with individual pathways (e.g., ballast, aquaculture, aquarium trade, fish stocking, hull
fouling, live bait).
The History and Development of the Guidelines
These Guidelines were modified from the US Aquatic Nuisance Species
Task Force’s Generic Non-indigenous Aquatic Organisms Risk Analysis
Review Process in 1996. The development of these Guidelines have been
synchronous with, and functionally tied to, the development of various
ecological risk assessments and with the international trade agreements
and their associated risk standards. The applicability of these guidelines
was recently reviewed (Leung and Dudgeon 2008).
In addition to the above projects and numerous other pertinent
works, the following quality criteria (modified from Fischoff et al.
1981) were used in designing the Guidelines:
• Comprehensive – The assessment should review the subject in
detail and identify sources of uncertainty in data extrapolation and
measurement errors. The assessment should evaluate the quality of its
own conclusions. The assessment should be flexible to accommodate
new information.
• Logically Sound – The risk assessment should be up-to-date and
rational, reliable, justifiable, unbiased, and sensitive to different aspects of the problem.
• Practical – A risk assessment should be commensurate with the
available resources.
• Conducive to Learning – The risk assessment should have a
scope sufficiently broad to carry over value for similar assessments.
The risk assessment should serve as a model or template for future
assessments.
• Open to Evaluation – The risk assessment should be recorded in
sufficient detail and be transparent enough in its approach that it can
be reviewed and challenged by qualified independent reviewers.
* 1-National Invasive Species Council, Washington, DC; and 2-ENVIRON International Corporation, Seattle, WA
Commission for Environmental Cooperation
3
Risk Analysis Philosophy
The risk assessment process allows for analyzing, identifying and estimating the dimension, characteristics and type of risk. By applying
analytical methodologies, the process allows the assessors to utilize
qualitative and quantitative data in a systematic and consistent fashion.
The ultimate goal of the process is to produce quality risk assessments on specific aquatic invasive organisms, or to evaluate those
non-indigenous organisms identified as being associated with specific pathways. The assessments should strive for theoretical accuracy
while remaining comprehensible and manageable, and the scientific
and other data should be collected, organized and recorded in a formal and systematic manner.
The assessment should be able to provide a reasonable estimation
of the overall risk. All assessments should communicate effectively the
relative amount of uncertainty involved and, if appropriate, provide
recommendations for mitigation measures to reduce the risk.
Caution is required to ensure that the process clearly explains
the uncertainties inherent in the process and to avoid design and
implementation of a process that reflects a predetermined result.
Quantitative risk assessments can provide valuable insight and understanding; however, such assessments can never capture all the
variables. Quantitative and qualitative risk assessments should always be buffered with careful professional judgment. Goals that
cannot be obtained from a risk assessment are:
1. A risk assessment cannot determine the acceptable risk level.
What risk, or how much risk, is acceptable depends on how a person,
agency, or country perceives that risk. Risk levels are value judgments
that are characterized by variables beyond the systematic evaluation
of information. Under existing international law each country has
the right to set its own acceptable risk level as long as they maintain
a degree of consistency in their risk decisions.
2. It is not possible to determine precisely whether, when, or how
a particular introduced organism will become established. It is equally
impossible to determine what specific impact an introduced organism
will have. The best that can be achieved is to estimate the likelihood
that an organism may be introduced and estimate its potential to do
damage under favorable host/environmental conditions.
The ability of an introduced organism to become established
involves a mixture of the characteristics of the organism and the
environment in which it is being introduced. The interaction between the organism and receiving environment largely determines
whether it fails or succeeds at invading, establishing and/or spreading. These factors cannot necessarily be predicted in advance by
general statements based only on the biology of the organism. In
addition, even if extensive information exists on a non-indigenous
organism, many scientists believe that ecological dynamics are so
turbulent and chaotic that future ecological events cannot be accurately predicted.
Figure 1. Risk Analysis Framework
Initiation
1. Request to evaluate a pathway
or
2. Request to evaluate a single organism
risk assessment
Identify scientific
and technical expertise
Create list of non-indigenous
organisms of concern
Create pathway data
Organism risk assesment(s)*
Pathway assesment assembled
Recommendation(s)
risk management
* For details on the Organism Risk Assessment see Figure 2 “Risk Assessment Model.” Pathways that show a high potential for introducing non-indigenous organisms should
trigger detailed risk analyses.
4
Trinational Risk Assessment Guidelines for Aquatic Alien Invasive Species
If all were certain, there would not be a need for risk assessment.
Uncertainty, as it relates to the individual risk assessment, can be
divided into three distinct types:
a) uncertainty of the process – (methodology)
b) uncertainty of the assessor(s) – (human error)
c) uncertainty about the organism – (biological and environmental unknowns)
Each one of these presents its own set of problems. All three
types of uncertainty will continue to exist regardless of future
developments. The goal is to succeed in reducing the uncertainty
in each of these groups as much as possible.
The “uncertainty of the process” requires that the risk methodologies involved with the Guidelines never become static or
routine but continue to be modified when procedural errors are
detected and/or new risk methodologies are developed.
“Uncertainty of the assessor(s)” is best handled by having the
most qualified and conscientious persons available conduct the assessments. The quality of the risk assessments will, to some extent,
always reflect the quality of the individual assessor(s).
It is the most difficult to respond to the “uncertainty about
the organism.” Indeed, it is the biological uncertainty more than
anything else that initiated the need for a risk process. Common
sense dictates that the caliber of a risk assessment is related to the
quality of data available for the organism and ecosystem that will
be invaded. Those organisms for which copious amounts of highquality research have been conducted are the most easily assessed.
Conversely, an organism for which very little is known cannot be
easily assessed.
A high degree of biological uncertainty, in itself, does not demonstrate a significant degree of risk. However, those organisms
that demonstrate a high degree of biological uncertainty do represent a real risk. The risk of importing a damaging non-indigenous
organism (for which little information is known) is probably small
for any single organism but the risk becomes much higher when
one considers the vast number of these organisms that must be
considered. It is not possible to identify which of the “unknowns”
will create problems—only to assume that some will.
The paucity of data does not mean that the organism will have no
negative impact, but it also does not mean that it will. Demonstrating that a pathway has a “heavy” concentration of non-indigenous
organisms for which little information is present may, in some cases
(based on the “type” of pathway and the “type” of organisms), warrant concern. However, great care should be taken by the assessor(s)
to explain why a particular non-indigenous organism load poses a
significant risk.
This need to balance risks with uncertainty can lead assessors to concentrate more on the uncertainty than on known facts
that may affect impact potential. Risks identified for alien invasive
species in other regions often provide the justification in applying management measures to reduce risks in other regions where
the species have not yet been introduced. Thus, risk assessments
should concentrate on evaluating potential risk.
Some of the information used in performing a risk assessment
is scientifically defensible, some of it may be anecdotal or based on
experience, and all of it is subject to the filter of perception. However, we must provide an estimation of risk based on the best information available and use that estimation in deciding whether to allow
the proposed activity involving the non-indigenous organism and, if
so, under what conditions.
Assessments should evaluate risk in order to determine the management actions that are commensurate with the identified risks. Estimations of risk are used to restrict, modify or prohibit, high risk pathways, with the goal of preventing the introduction of invasive species.
The following quote is taken from the NRC (1983) Red Book, entitled Risk Assessment in the Federal Government: Managing the Process:
We recommend that regulatory agencies take steps to establish
and maintain a clear conceptual distinction between assessment of risks and consideration of risk management alternatives; that is, the scientific findings and policy judgments embodied in risk assessments should be explicitly distinguished
from the political, economic, and technical considerations that
influence the design and choice of regulatory strategies.
This can be translated to mean that risk assessments should not be
policy-driven. However, the Red Book then proceeded with a caveat:
The importance of distinguishing between risk assessment
and risk management does not imply that they should be
isolated from each other; in practice, they interact, and
communication in both directions is desirable and should
not be disrupted.
This can be translated to mean that the risk assessment, even
though it must not be policy-driven, must be policy-relevant. These
truths continue to be valid (NRC 1993).
The Guidelines for Conducting Pathway Assessment and Organism Risk Assessments
The need for a risk assessment starts either with the request for opening a new pathway that might harbor aquatic invasive organisms, or
the identification of an existing pathway that may be of significant
risk. All pathways showing a potential for non-indigenous organism
introduction should receive some degree of risk evaluation. Those
pathways that show a high potential for introducing non-indigenous
organisms should trigger an in-depth risk assessment.
Continuous open communication between the risk managers
and the risk assessors is important throughout the writing of the risk
assessment. This is necessary to ensure that the assessment will be
policy relevant when completed. Risk managers should be able to
provide detailed written questions that they need answered to the
risk assessors before the risk assessment is started. This will allow the
assessors to focus the scientific information relevant to the questions
(issues) that the risk managers will need to address.
The following details of the Guidelines focus on evaluating the
risk of non-indigenous organisms associated with an identified pathway. Figure 1 outlines the flow of a pathway analysis, dividing the process into initiation, risk assessment, and risk management. Specific
organisms needing evaluation which are not tied to a pathway assessment would proceed directly to the “Organism Risk Assessments”
box in Figure 1 and the “Organism Risk Assessments” section.
Collecting Pathway Data
Specific information about the pathway must be collected. This information, coupled with additional data would fulfill the “Collect
Pathway Data” element in Figure 1.
Specific information needed about the pathway will vary with the
“type” of pathway (e.g., ballast water, aquaculture, aquarium trade,
Commission for Environmental Cooperation
5
Table 1. Screening Tool
Category
Organism Characteristics
Concern
1a
species non-indigenous, not present in country
yes
1b
species non-indigenous, in country and capable of further expansion
yes
1c
species non-indigenous, in country and reached probable limits of range, but
genetically different enough to warrant concern and/or able to harbor another
non-indigenous pest and/or introduce risk of hybridization
yes
1d
species non-indigenous, in country and reached probable limits of range and
not exhibiting any of the other characteristics of 1c
no
2a
species indigenous, but genetically different enough to warrant concern and/or
able to harbor another non-indigenous pest, and/or capable of further expansion and/or introduce risk of hybridization
yes
2b
species indigenous and not exhibiting any of the characteristics of 2a
no
fish stocking). The following generalized list of information has been
useful in other non-indigenous risk assessments:
1) Determine exact origin(s) of organisms associated with the pathway.
2) Determine the numbers of organisms traveling within the pathway.
3) Determine intended use, or disposition, of pathway.
4) Determine mechanism and history of pathway.
5) Review history of past experiences and previous risk
assessments (including foreign countries) on pathway or
related pathways.
6) Review past and present mitigating actions related to the pathway.
Creating a List of Aquatic Invasive Organisms of Concern
One element identified in Figure 1 is the need to “Create List of Nonindigenous Organisms of Concern.” To create such a list, the following generalized process is recommended:
1) Determine what organisms are associated with the pathway.
2) Determine which of these organisms qualify for further
evaluation using the table below.
3) Produce a list of the organisms of concern from (step 2)
categories 1a, 1b, 1c, and 2a. Taxonomic confusion or
uncertainty should also be noted on the list.
4) Conduct organism risk assessments from the list of
organisms developed in step 3.
Based on the number of organisms identified and the available
resources, it may be necessary to focus on fewer organisms than those
identified using the above table. When this is necessary, it is desirable
that the organisms chosen for complete risk assessments be representative of all of the organisms identified. A standard method is not
available because the risk assessment process is often site or species
specific. Therefore, professional judgment by scientists familiar with
the aquatic organisms of concern is often the best tool to determine
which organisms are necessary for effective screening. This screening can be done using alternative approaches. Different approaches
can be found in each of the three log commodity risk assessments
(USDA Forest Service 1991, 1992, 1993).
6
Organism Risk Assessment
The Organism Risk Assessment element in Figure 1 is the most important component of the Guidelines used in evaluating and determining
the risk associated with a pathway. The Organism Risk Assessment can
be independent of a pathway assessment if a particular non-indigenous
organism needs to be evaluated. Figure 2 represents the Risk Model that
drives the Organism Risk Assessment.
The Risk Assessment Model is divided into two major components: “Probability of Establishment” and the “Consequence of Establishment.” This division reflects how one can evaluate a non-indigenous organism (e.g. more restrictive measures are used to lower
the probability of a particular non-indigenous organism establishing
itself when the consequences of that establishment are greater).
The Risk Assessment Model is a working model that represents
a simplified version of the real world. In reality, the specific elements
of the Risk Model are not static or constant, but are dynamic showing
distinct temporal and spatial relationships. Additionally, the elements
are not equal in weighing the risk, nor are they necessarily independent.
The weight of the various elements will never be static because they
are strongly dependent upon the non-indigenous organism and its
environment at the time of introduction.
The two major components of the Risk Assessment Model are
divided into seven basic elements that serve to focus scientific, technical,
and other relevant information into the assessment. Each of these seven
basic elements is represented on the Organism Risk Assessment Form
(Appendix A) as probability or impact estimates. The individual elements may be determined using quantitative or subjective methods.
The strength of the assessment is that the information gathered
by the assessor(s) can be organized under the seven elements. The cumulative information under each element provides the data to assess
the risk for that element. Whether the method used in determining
the risk for that element is quantitative, qualitative or a combination
of both, the information associated with the element (along with its
references) will function as the information source. Placing the information in order of descending risk under each element will further
communicate to reviewers the thought process of the assessor(s).
Adequate documentation of the information sources makes the
Guidelines transparent to reviewers and helps to identify information
gaps. This transparency facilitates discussion if scientific or technical
Trinational Risk Assessment Guidelines for Aquatic Alien Invasive Species
disagreement on an element-rating occurs. For example, if a reviewer
disagrees with the rating that the assessor assigns an element, the reviewer can point to the information used in determining that specific
element-rating and show what information is missing, misleading,
or in need of further explanation. Focusing on information to
resolve disagreements will often reduce the danger of emotion or
a preconceived outcome from diluting the quality of the elementrating by either the assessors or the reviewers.
The specific questions and rationale for each of the Risk Assessment Model elements addressed are listed below. Note: when evaluating an organism that is not associated with a pathway, or an organism
recently introduced, the answer to the first two Group 1 questions
below would automatically be rated as “high” because entry into the
new environment is either assumed or has already occurred.
A. Elements - Group 1: Assess Probability of Organism
Establishment
1. Aquatic Non-indigenous Organisms Associated with Pathway
(At Origin) – Estimate probability of the organism being on, with, or in
the pathway.
The major question inherent to this calculation is: does the organism show a convincing temporal and/or spatial association with
the pathway? For example, hull fouling of recreational boats has been
shown to provide a viable pathway for the introduction of the zebra
mussel into uncolonized waters of North America from the lower Great
Lakes, although a different pathway (ballast water) is recognized as re-
sponsible for their initial introduction into the Great Lakes.
2. Entry Potential – Estimate probability of the organism surviving in transit.
The entry potential considers the probability of that the organism in the pathway could enter (i.e., be released) into the environment of concern. Some of the characteristics of this element include: the organism’s hitchhiking ability in commerce; its ability to
survive during transit; the stage of life cycle of the organism during
transit; the number of individuals expected to be associated with
the pathway; and/or whether it is deliberately introduced (e.g., as a
biocontrol agent or for fish stocking). For many species that would
be evaluated under these guidelines, the probability of entry would
be considered “1” (i.e., 100%). Typical examples would include species released for biological control or sport fishing opportunities
such as mosquito fish (Gambusia spp.) for mosquito control, and
smallmouth bass for recreational fisheries into waters west of the
continental divide. In other cases, a species may be intentionally
brought into a region where it is not indigenous through commerce,
but its probability of entry into the environment is less than 100%.
The importation of snakehead fishes in the live food trade represents a typical example of this case.
3. Colonization Potential – Estimate probability of the organism
colonizing and establishing a reproductively viable population.
Some of the characteristics that should be considered in this
analysis include: the potential for the organism to obtain adequate
Figure 2. Risk Assessment Model
Standard Risk Formula
Risk =
Probability
of establishment
Consequence
of establishment
Elements of model
Risk =
Organism
Entry
Colonization
Spread
with
x Potential x Potential x Potential
Pathway
Economic
Impact
Potential
+
Environmental
Impact
Potential
+
Social and
Cultural
Impact
For model simplification, the various elements are depicted as being independent of one another. That is, the order of the elements in the
model does not necessarily reflect the order of calculation.
Commission for Environmental Cooperation
7
food resources; abiotic and biotic environmental resistance factors (e.g., geographical and temporal associations); propagule
pressure—the number of individuals likely to be introduced via
the pathway; and, the ability to reproduce or hybridize in the new
environment. This qualitative estimation must consider whether
the environmental factors, such as water quality, climate, and
physical habitat components like temperature, structure, and flow,
are within the environmental tolerance limits of the organism to
permit a self-reproducing population to be established.
4. Spread Potential – Estimate probability of the organism spreading beyond the colonized area.
Some of the characteristics of this element include: ability for
natural dispersal, ability to use human activity for dispersal, ability
to readily develop races or strains, and the estimated range of probable spread based on the availability of suitable habitat conditions.
For example, Genetic Algorithm for Rule-Set Projection (GARP)
modeling considers a variety of climatic variables in the native range
of an organism and applies that information to evaluate the potential
spread of an organism, or class of organisms, in new environments
that may share those climatic conditions. (see Peterson and Vieglais
2001, Kolar 2004, and Herborg et al. 2007).
B. Elements – Group 2: Assess Consequence of Establishment
1. Economic Impact Potential – Estimate economic impact if established.
Some of the characteristics of this element of the guidelines include: economic importance of hosts, damage to crop or natural resources, effects to subsidiary industries, exports, lost ecological services, and direct control and management costs. Economic impacts
may be calculated from direct monetary expenditures that result
from the damage caused by the species, such as the costs required to
clean water intake lines of zebra mussels. A monetary assessment of
the loss of ecosystem goods and services may also be calculated but
the uncertainty with these estimates will likely be higher.
2. Environmental Impact Potential – Estimate environmental impact if established.
Some of the characteristics of this element include: ecosystem destabilization or modification or degradation, reduction in native biodiversity from the loss or reduction in quality of preferred habitats, reduction or elimination of keystone species, reduction or elimination of
endangered/threatened species, loss or reduction in quality of preferred
habitat conditions for native species, and impacts of future control actions. If appropriate, impacts on the human environment (e.g., human
parasites or pathogens) would also be captured under this element.
8
3. Social and Cultural Influences – Estimate impact to social and
cultural practices.
Some of the characteristics of this element include: impacts to
aboriginal cultures and other cultures of national and regional importance, and social impacts that are not easily captured under the
economics elements.
The elements considered in the “Consequences of establishment” box in Figure 2 can also be used to record positive impacts
that a non-indigenous organism might have, e.g., its importance as
a biocontrol agent, pet, sport fish, scientific research organism, or
its use in aquaculture. The elements in the case of deliberate introductions would record information that will be useful in determining the element-rating that provide a balance between the cost, the
benefit, and the risk of introducing the non-indigenous organism.
The Organism Risk Assessment Form (Appendix A) should be
flexible. Each non-indigenous organism is unique and the assessor
needs to have the freedom to modify the form to best represent the
risk associated with that particular organism. However, the seven
elements need to be retained to estimate the risk. If the assessor
feels additional information, ideas, or recommendations would
be useful, they should be included in the assessment. The assessor
can combine “like” organisms into a single assessment if their biology is similar (e.g., tropical aquarium fish destined for temperate
North America).
The number of risk assessments to be completed from the list
of non-indigenous organisms in a particular pathway (Figure 1)
depends on several factors. These include the amount of information on the organism, the available resources, and the assessor’s professional judgment concerning whether the completed
assessments effectively represent the pathways’ non-indigenous
organism risk.
The source of the information under each element and the degree of uncertainty the assessor associated with each element needs
to be recorded in the Risk Assessment. The use of the Reference Codes
at the end of each statement, coupled with the use of the Uncertainty
Codes for each element, fulfill these requirements. (Reference Codes
and Uncertainty Codes are described in Appendix A.)
Summarizing Organism and Pathway Risk
An estimate of risk is made at three levels in the Guidelines. The
first level places a risk estimate on each of the seven elements within
the Risk Assessment (element-rating). The second level combines
the seven risk element estimates into an Organism Risk Potential
(ORP), which represents the overall risk of the organism being assessed. The third level links the various ORPs into a Pathway Risk
Potential (PRP), which will represent the combined risk associated
with the pathway.
Trinational Risk Assessment Guidelines for Aquatic Alien Invasive Species
The most difficult steps in a risk assessment are assigning
quantitative or qualitative estimates to an individual element, determining how the specific elements in the model are related, and
deciding how the estimates should be combined. There is no “correct” formula for completing these steps. Various methods such as
geographical information systems, climate and ecological models,
decision-making software, expert systems, and graphical displays
of uncertainty, may potentially increase the precision of one or
more elements in the Risk Assessment Model. Indeed, risk assessments should never become so static and routine that new methods
cannot be tested and incorporated.
When evaluating new approaches, it is important to keep in
mind that the elements of the Risk Assessment Model are dynamic,
and not equal in value. New approaches appropriate for assessing
one organism may be immaterial or even misleading in evaluating
another organism.
The strength of the Guidelines is that the biological statements
under each of the elements provide the raw material for testing
various approaches. Therefore, the risk assessment will not need
to be re-done to test new methods for calculating or summarizing
the ORP and PRP.
On risk issues of high visibility, examination of the draft assessment should be completed by pertinent reviewers not associated with the outcome of the assessment. This is particularly appropriate when the risk assessments are produced by the same agency,
professional society, or organization responsible for the management of that risk.
Components of the Final Assessment
• Introduction
• Pathway information
• A complete list of the organisms of concern
• The individual Organism Risk Assessments
• Response to specific questions requested by risk managers
• Summation of the methodology used in determining the ORPs and PRPs
• Summation and responses to outside reviewers
Commission for Environmental Cooperation
9
APPENDIX A
Organism Risk Assessment Form
ORGANISM RISK ASSESSMENT FORM
(With Uncertainty and Reference Codes)
ORGANISM FILE NO.
ASSESSOR DATE
PATHWAY ORIGIN ORIGIN
I. LITERATURE REVIEW AND BACKGROUND INFORMATION (summary of life cycle, distribution, and natural history):
II. PATHWAY INFORMATION (include references):
III. RATING ELEMENTS: Rate statements as low, medium, or high. Place specific biological information in descending order of risk with reference(s) under each element that relates to your estimation of probability or impact. Use the reference codes at the end of the biological statement where appropriate and the Uncertainty Codes after each element rating.
PROBABILITY OF ESTABLISHMENT
Element
Uncertainty
Rating
Code
(L,M,H)
(VC - VU)
ELEMENTS
Estimate probability of the non-indigenous organism being on, with, or in the pathway.
(Supporting Data with reference codes)
Estimate probability of the organism surviving in transit.
(Supporting Data with reference codes)
Estimate probability of the organism successfully colonizing and maintaining a population where introduced.
(Supporting Data with reference codes)
Estimate probability of the organism to spread beyond the colonized area.
(Supporting Data with reference codes)
CONSEQUENCE OF ESTABLISHMENT
Element
Rating
(L,M,H)
Uncertainty
Code
(VC - VU)
10
ELEMENTS
Estimate economic impact if established.
(Supporting Data with reference codes)
Estimate environmental impact if established.
(Supporting Data with reference codes)
Estimate impact from social and/or cultural influences.
(Supporting Data with reference codes)
Trinational Risk Assessment Guidelines for Aquatic Alien Invasive Species
I. ORGANISM/PATHWAY RISK POTENTIAL: (ORP/PRP) ___________________________________________________________
Probability Consequence
of
of Establishment Establishment
= ORP/PRP RISK
II. SPECIFIC MANAGEMENT QUESTIONS
III. RECOMMENDATIONS
IV. MAJOR REFERENCES
REFERENCE CODES TO ANSWERED QUESTIONS
Reference CodeReference Type
(G)General Knowledge, no specific source
(J)Professional Judgment
(E)Extrapolation; information specific to pest not available; however, information available on similar organisms applied
(Author, Year)Literature Cited
UNCERTAINTY CODES TO INDIVIDUAL ELEMENTS
(based as much as possible on peer-reviewed science)
Uncertainty Code
Symbol
Description
Very Certain
VC
As certain as I am going to be
Reasonably Certain
RC
Reasonably certain
Moderately Certain
MC
More certain than not
Reasonably Uncertain
RU
Reasonably uncertain
Very Uncertain
VU
An educated guess
Commission for Environmental Cooperation
11
Bibliography
ANSTF. 1996. Generic Nonindigenous Aquatic Organisms Risk Analysis Review Process (For Estimating Risk Associated with the Introduction of Nonindigenous Aquatic Organisms and How to Manage for
that Risk). Report to the Aquatic Nuisance Species Task Force by the
Risk Assesment and Management Committee. October 21, 1996. See
http://www.anstaskforce.gov/Documents/ANSTF_Risk_Analysis.pdf.
Fischoff, B., S. Lichtenstein, P. Slovic, S.L. Derby, and R.L. Keeney.
1981. Acceptable risk. London, UK: Cambridge University Press.
Herborg, L.-M., C.L. Jerde, C.L., D.M. Lodge, G.M. Ruiz, and H.J.
MacIsaac. 2007. Predicting invasion risk using measures of introduction effort and environmental niche models. Ecological Applications
17(3): 663–674. The Ecological Society of America. See http://web2.
uwindsor.ca/courses/biology/macisaac/pages/matt.pdf.
Kolar, C. 2004. Risk assessment and screening for potentially invasive fishes. New Zealand Journal of Marine and Freshwater Research
38: 391–397. The Royal Society of New Zealand.
Leung, K.M.Y., and D. Dudgeon. 2008. Ecological risk assessment
and management of exotic organisms associated with aquaculture activities. In M.G. Bondad-Reantaso, J.R. Arthur and R.P. Subasinghe
(eds). Understanding and applying risk analysis in aquaculture. FAO
Fisheries and Aquaculture Technical Paper. No. 519. Rome, FAO. pp.
67–100.
National Research Council (NRC). 1983. Risk Assessment in the Federal Government: Managing the Process. Washington, DC: National
Academy Press.
National Research Council (NRC). 1993. Issues in Risk Management.
Washington, DC: National Academy Press.
Peterson, A.T., and D.A. Vieglais. 2001. Predicting species invasions
using ecological niche modeling: new approaches from bioinformatics attack a pressing problem. BioScience 51(5): 363-371. May.
US Department of Agriculture (USDA). Forest Service, 1992. Pest
Risk Assessment of the Importation of Pinus radiata and Douglas Fir
Logs from New Zealand. Miscellaneous Publication No. 1508.
USDA Forest Service. 1993. Pest Risk Assessment of the Importation
of Pinus radiata, Nothofagus dombeyi and Laurelia philippiana Logs
from Chile. Miscellaneous Publication No. 1517.
USDA Forest Service. 1991. Pest Risk Assessment of the Importation
of Larch from Siberia and the Soviet Far East. Miscellaneous Publication No. 1495.
Commission for Environmental Cooperation
393, rue St-Jacques Ouest, Bureau 200
Montréal (Québec) Canada H2Y 1N9
t (514) 350-4300 f (514) 350-4314
[email protected] / www.cec.org